MODELLING BIOMETRIC TRAITS AND STRAW YIELD OF WHITE MUSTARD (Sinapis alba L.) GROWN FOR SEEDS BY THE SOWING DATE AND METEOROLOGICAL FACTORS
Background. White mustard is a plant with good yield stability, low variability in the length of the growing season and a considerable resistance to climatic factors. However, delaying the sowing date of this plant results in significant changes in the plant habit and yield.
Material and methods. A three-year field experiment with white mustard cultivated for seeds was carried out as a one-factor, in the randomized block design in four replications. White mustard was sown on 13 dates at intervals of seven days, from the beginning of April to the turn of June and July, and harvested after reaching seed maturity.
Results. Delaying the sowing date of the white mustard cultivar 'Nakielska' grown for seeds from an early spring date resulted in changes to the plant habit. There was a reduction of plant height and an increased tendency to form low-productivity higher-order lateral branches, a reduction in both the number of siliques on the main stem and the number of seeds in siliques from the main stem and lateral stems.
Conclusion. Delaying white mustard sowing resulted in limiting the height of plants and increasing the tendency to form higher-order lateral branches. It was shown that the straw yield, the number of siliques on the main stem and the number of seeds in siliques from both the main stem and lateral stems were reduced as a result of delayed sowing. The shorter was the day after the summer solstice when the white mustard came into the next development phase, the smaller the number of yield structural components the plants were characterized by. The crops of white mustard from successive dates differed in their canopy structure because the field emergence capacity of seeds was deteriorating, which resulted in a lower plant density after emergence, an increase in plant loss during the growing season and a decrease in the straw yield.